This invention relates to improvements in ocean going cargo transport systems and more particularly concerns an improved cargo carrier of the type employing a cargo unit vessel and detachable control module and power module vessels. The invention is herein illustratively described by reference to the presently preferred embodiment thereof; however, it will be recognized that certain modifications and changes therein with respect to details may be made without departing from the essential features involved.
It has long been recognized that oceanic cargo ships of conventional design sufficiently large for economic operation on long voyages lose much of those savings in loading and unloading costs and tie-up time; also in the limitation on ports accessible to them, primarily the major deep water ports. Moreover, not only does the typical ship's displacement type hull necessary for efficient safe crossings require an extreme draft for these huge vessels, but the shape and depth of the hull, together with the presence and arrangement of propulsion plants and other ship's machinery, quarters and gear, makes the resulting storage space configurations and arrangements quite ill-suited to the efficient and versatile utilization of the net tonnage hold capacity of the vessel, particularly for general cargo ships as distinguished from tankers wherein storage space configuration is obviously of lesser importance.
A major effort in recent years to reduce loading and unloading costs is seen in the advent of containerized cargo ships and barges. However, with barges, speed is limited and travel time becomes excessive over long distances. Furthermore, a large container ship cannot enter many of the shallow-water ports, so that additional trans-shipping costs are incurred in those cases. Somewhat similar problems are encountered in the large roll-on, roll-off ships such as are used to transport automobiles and the like.
The lighters-aboard-ship type vessels (referred to as LASH) permit servicing of shallow-water ports, such as upriver ports, but again, as in the case of container ships of conventional design, these also are not highly versatile and are incapable of fully utilizing hold space.
All of these ships in the larger sizes are very expensive to build because of the multiple complex curvatures in virtually all portions of a displacement type hull as well as the requirements of complex framing, and providing for the accommodation and mounting of heavy and bulky power plants and other machinery, quarters, and ship's equipment. Moreover the requirements of a large on-board crew to man such vessels not only imposes expensive space and facilities requirements, but also adds operating costs both in terms of wages, fringes and supplies and in terms of lost cargo space otherwise available.
A broad object of the present invention is to devise a high-speed, high-capacity, oceanic cargo carrier of shallow draft configuration readily and efficiently adaptable to substantially any of the specialized or general purpose cargo, container, lighter or tanker vessel applications heretofore utilized. More specifically, it is an object to provide a vessel of such shallow draft yet such relatively large load capacity as will permit the same to navigate in shallow harbors without penalizing its capability of operating safely and efficiently on the high seas.
A further object hereof is to devise an ocean transport system wherein a cargo carrier vessel hull having the desirable box-like or rectangular basis cross-sectional configuration somewhat characteristic of a "barge" is achieved for efficient and versatile utilization of hold and deck space. Yet it will be equipped with such a bow and stern configuration and related propulsion means as to safely attain the high cruising speeds expected of modern ships in trans-oceanic service.
The combinational effect of the general hull configuration having the novel bow form of this invention reduces accumulative pitch and roll tendencies experienced with conventional ship's hulls; also yaw reactions to pitch and roll in quartering seas. Thus held in more nearly level trim laterally in a variety of sea conditions higher cycle loading can be safely permitted. Likewise, because of the decreased pitching tendency and the special bow effects achieved, the improved vessel attains an increased driving efficiency in heavy seas.
It is also an object to devise an ocean going transport system wherein effective utilization of separate propulsion module vessels and control module vessel, detachable from the cargo unit vessel, makes possible use of a smaller crew to man the overall system than with a ship of conventional design and comparable capacity. Moreover, safety of the crew is enhanced by the independent sea-going capability of the detachable power module and control module vessels when decoupled from the cargo unit vessel.
A related objective hereof is to devise an ocean going transport system of the nature indicated which may be of relatively low cost, sturdy construction, yet because of the special bow configuration, capable of withstanding the heavy impact forces of waves and swells on the bow at high cruising speeds. Furthermore, the special bow and stern configurations of the cargo unit vessel hull permits utilizing a flat-bottomed straight vertical-sided midship or waist section over most of the length of the hull, simplifying the lofting framing, plating, jigging and general construction of the overall vessel.
Still another object hereof is to devise an improved transport system with novel control module vessel having a helm station arrangement enabling the helmsman and crew to observe and monitor all parts of the system and to operate from an elevated vantage point with good visibility over the loaded cargo unit vessel ahead of it.
More specific objects relate to a novel and improved construction for the power module vessels, which are to be detachably coupled with the cargo unit vessel to propel the same. Special low cost drive unit, housing and flotation collar arrangements, together with vertical adjustability of the drive units in relation to the cargo vessel hull enables the propulsion line of forces to be raised and lowered and thereby vary the trim of the cargo unit vessel fore and aft for greatest safety and efficiency in cruise. Adjustable couplings between the power module vessels and the cargo unit vessel accommodate or permit such variations in thrust line produced by the propulsion vessel propellers.